title: Alternate transcripts of a floral developmental regulator have both distinct and redundant functions in opium poppy.
abstract: OBJECTIVE
  The MADS-box transcription factor AGAMOUS (AG) is an important regulator of stamen and fruit identity as well as floral meristem determinacy in a number of core eudicots and monocots. However, its role outside of these groups has not been assessed explicitly. Examining its role in opium poppy, a basal eudicot, could uncover much about the evolution and development of flower and fruit development in the angiosperms.
  
  
  METHODS
  AG orthologues were isolated by degenerate RT-PCR and the gene sequence and structure examined; gene expression was characterized using in situ hybridization and the function assessed using virus-induced gene silencing.
  
  
  RESULTS
  In opium poppy, a basal eudicot, the AGAMOUS orthologue is alternatively spliced to produce encoded products that vary at the C-terminus, termed PapsAG-1 and PapsAG-2. Both transcripts are expressed at high levels in stamens and carpels. The functional implications of this alternative transcription were examined using virus-induced gene silencing and the results show that PapsAG-1 has roles in stamen and carpel identity, reflecting those found for Arabidopsis AG. In contrast, PapsAG-2, while displaying redundancy in these functions, has a distinctive role in aspects of carpel development reflected in septae, ovule and stigma defects seen in the loss-of-function line generated.
  
  
  CONCLUSIONS
  These results describe the first explicit functional analysis of an AG-clade gene in a basal eudicot; illustrate one of the few examples of the functional consequences of alternative splicing in transcription factors and reveal the importance of alternative transcription, as well as gene duplication, as a driving force in evolution.
authors.affiliation: Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Hands
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Vosnakis
authors.forename: Donna
authors.initials: D
authors.lastname: Betts
authors.forename: Vivian F
authors.initials: VF
authors.lastname: Irish
authors.forename: Sinéad
authors.initials: S
authors.lastname: Drea
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D035264:Flowers / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D020440:Gene Duplication; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010207:Papaver / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D018744:DNA, Plant; D026161:MADS Domain Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D014157:Transcription Factors